Magnetic valve for well plunger



Sept. 25, 1962 G. H TAUSCH MAGNETIC VALVE FOR WELL PLUNGER Filed 001;.26, 1960 6. /7. 7270-3 cfi INVENTOR.

BY 2Q (AL Staes Patented Sept. 25, 1962 3,055,306 MAGNETIC VALVE FORWELL PLUNGER Gilbert H. Tausch, Houston, Tex., assignor to Cameo,Incorporated, Houston, Tex., a corporation of Texas Filed Oct. 26, 1960,Ser. No. 65,029 Claims. (Cl. 103-52) This invention relates to theelevation of liquids through a well eduction tube under influence ofpressure gas delivered to the eduction tube below its liquid level, andmore particularly to a free piston plunger closely fitting thetube forrise and fall between opposite limits therein and having an upwardlyseating check valve controlling a pressure equalizing passagecommunicating the tube space above and below the plunger.

Plunger lift systems, Whether dependent on formation pressure or outsidepressure gas supplied and regulated by a surface timer, have long beenin use and in general are arranged in the manner disclosed in FletcherPatent 1,846,000, dated February 16, 1932. On plunger downstroke, anopen passage across the plunger permits its gravity descent through wellfluids and at the lower limit of travel a valve engages a striker landis shifted to passage closing relation, whereupon fluid pressure belowthe plunger raises the same and pushes any liquid thereabove to thesurface. At the upper limit, a bumper engagement returns the valve toopen position for a pressure equalizing action and a repeated plungerdownstroke.

Satisfactory valve action is of critical importance and has been atroublesome problem and an object of the present invention is to provide:an improved valve structure which will be reliable and care free foreffective operation throughout long periods of use.

A further object of the invention is to provide a simplified valvestructure comprising but a few inexpensive and easy to manufacture andassemble elements and which will hold itself in closed position as wellas open position without reliance entirely on fluid pressuredifferentials or on movable position controlling parts inclusive oflatching detents, springs or other items likely to get out of order fromwear, strain and the wide range of temperature change encountered indeep well installations.

Another object of the invention is to provide an improved plunger whosebody adjacent its annular passage seat includes a valve cage having avalve abutment shoulder below the seat, with the shoulder and seataffording spaced apart limit stops and defining the travel range of ashiftable check valve which incorporates a longitudinally magnetizedpermanent magnet whose end portions and opposite poles co-operate withthe limit stops and the cage wall whereby lines of magnetic force haveeffective valve holding action in both closed and open relationships andprovide predetermined resistance to displacement of the shiftable valvefrom either position at which the valve has been set.

Other objects and advantages will be apparent from inspection of theaccompanying drawing wherein FIG. 1 is an elevation partly in sectionshowing a plunger having a check valve in its open position and FIG. 2is a similar view of a modified embodiment of the invention.

In the plunger as shown in FIG. 1, there is included a hollow bodymember comprising an elongated central tube 1 and enlarged upper andlower heads 2 and 3 threaded onto opposite ends of the tube 1. Theuppermost tubular head 2 terminates upwardly in the usual fishing neckcoupling and between it and the bottom head 3 are clamped in surroundingrelation to the central tube 1, a stack of sealing assemblies which arefor co-operation with the eduction tube wall in restricting fluidpassage around the plunger assembly. These elements include a sleeve 4having an alternate succession of pcripheral ribs and grooves to providea labyrinth type seal. In addition, FIG. 1 shows a pair of sleeves 5 and6 in end to end succession, each having a pair of diametrically oppositewindows extending longitudinally therein from adjoining edges andreceiving wiping shoes 7 suitably retained in the sleeves, as by meansof end tabs 8 which project above and below each window and fit thehollow sleeves to limit outward travel of the shoes under influence oflaterally disposed coil springs 9. Each wiper shoe 7 has an arcuatelength exceeding ninety degrees and the pair of shoes received withinthe window of the sleeve 5 are angularly spaced from the pair of shoes 7fitted [to the companion sleeve 6.

The lowermost coupling head 3 is hollow and immediately below its upperscrew threaded end portion it has an enlarged cylindrical chamber 10 ofuniform diameter throughout its length which forms a continuation of thepassageway through the hollow tube 1 and communicates with the outsideof the plunger and below the sealing elements through one or morelateral ports 11. At its upper end, the chamber 10 encloses an annularand upwardly tapered valve seat 12 formed either as a part of thecoupling head 3 or as the bottom end of the tube 11, as shown in thedrawing.

For co-operation with the fixed annular seat 12 and slidably caged orcontained within the chamber 10 is a check valve assembly for movementtoward and from the seat 12. This check valve includes a central stem 13which slidably fits and projects through a reduced diameter bore leadingdownwardly from the chamber 10 from an adjacent shoulder 14 at thetbottom of the chamber. A reduced diameter upper portion of the stemprovides an intermediate upwardly facing shoulder thereon to which isfitted a washer 15 at the lower end of an annular magnet 16 Whose upperend is overlapped by a washer 17 threaded on or otherwise secured to theupper end of the stem 13. Peripherally enclosing the cylindrical magnet16 and extending between the upper and lower washers 15 and 17 is afacing sleeve 18 of brass or other suitable nonmagnetic material andpreferably of uniform outside diameter throughout its length. Theassembly comprising sleeve 18 and magnet 16 and the washers 15 and 17has a slight and uniform clearance re laden with the interior surface ofthe chamber 10 and is an over-all length somewhat less that the lengthof the chamber 10, sufficient to accommodate movement of the valvetoward and from the seat 12. The upper washer 17 has an upwardly taperedrim portion to mate with and tightly engage with the tapered seat 12when the valve is raised. Bearing on the upper face of the washer 17 isthe lower end of .a longitudinally fluted or grooved rod 19 extendingthrough the passage the tube 1 and terminating upwardly in a reduced pinportion 20 slida-bly projectable through the upper end of the couplinghead 2. In the position of the parts seen in FIG. 1, the check valve isat its lower open limit for free movement of liquid by way of the ports11 and the longitudinal grooves in the rod 19 which lead to lateralports 21 in the coupling 2. This is the relationship of the parts whichenables gravity descent of the plunger until the projecting lower tipportion of the stem 13 strikes an abutment at the lower limit of travel,whereupon the valve seat 12 and body assembly move downwardly until theseat 12 in engagement with the mating seat on the check valve assemblyfor closing the passage, Incident to such relative movement, the uppertip portion 20 of the fluted rod will be projected upwardly above theplunger, and with the valve seated, pressure below the plunger willelevate it until the tip 20 comes into abutment with a suitable strikerat the well head and holds the check valve stationary while the mainbody and seat 12 rise for opening the passageway until the seatingshoulder 14 engages the bottom of the check valve.

The annular magnet 16 is magnetized longitudinally of its length so thatits opposite poles are spaced apart in the longitudinal direction. Thewall of the cage is formed of ferrous or magnetic material andco-operates with the field of the magnet and since the radial clearancerelation between the opposite poles and the cage wall is similar at bothends of valve travel, the magnetic holding force will be effectivewhether the valve is in open or closed position. That is to say, whenthe check valve is bodily moved from one position to the other, thelines of force of the permanent magnet are overcome for accommodatingthe movement and then act through the valve cage for resistingdisplacement. This holding action is of special consequence in the valveclosing position under conditions in which the fluctuations in pressure,which normally tends to act upwardly on the closed valve, are ofsufficiently wide variation during upward plunger travel as to allow thevalve to unseat itself. The holding force is also of importance in theopen position of the valve in resisting any closing forces duringdownward plunger travel.

The improved result obtained with the use of a permanent magneteliminates need for locating springs and poppet devices, such as oftenused heretofore, and insures a positive and reliable action without wearout and breakage of parts. As previously indicated, the facing sleeve 18is of nonmagnetic material. Its use as an optional feature is tominimize accumulation of metal debris on the valve assembly. As proposedin the embodiment disclosed, the valve stem 13 and the elongated motiontransmitting rod 19 are of nonmagnetic material whereas the cage 3,containing the seating shoulder 14, and the tubular body 1, presentingthe valve seat 12, are of magnetic material. Also, the end washers 15and 17 in bottom and top face contact with the permanent magnet are ofmagnetic material and constitute pole pieces for extending andconcentrating the magnetic field. This arrangement is preferred for aneffective holding action when the shiftable valve is engaged with eitherthe magnetic seat 14 or the magnetic seat 12. In both valve positions,the cage affords a flux path between the magnet poles with similar smallgap reluctance due to uniform cylindrical clearance throughout the valvetravel range.

The magnet-valve assembly and cage arrangement just described isincorporated in the modified plunger of FIG. 2 except that there isabsent the long push rod 19 in the passageway in the tube 1 above itsbottom valve seat 12. Instead, a dependent rod 19a is fixedly mounted inthe lubricator assembly at the well head and is of such length that itwill be telescopically received in the body of the plunger and projectdownwardly through the central passageway therethrough into strikingengagement with the top of the magnetic valve at the upper limit ofplunger travel. As an optional sealing arrangement for wiping engagementwith the eduction tube, the peripherally ribbed sleeve 4 shown in FIG. 1is omitted in FIG. 2 and is replaced by a second set of four wiper shoes7 indentical in structure and arrangement to the set of shoes shown anddescribed in connection with FIG. 1. In other words, there are two setsof four co-operating wiper shoes and locating sleeves 5 and 6 and thetwo sets are arranged in tandem assembly relationship.

While the foregoing specification has been limited to specificstructure, it is to be understood that various modifications can be madewithout departing from the invention as set forth in the attachedclaims.

What is claimed is:

1. A free plunger for travel through a well eduction tube and betweenupper and lower limit stops therein, a hollow body having a passagetherethrough and a downwardly facing valve seat fixed in the passage, acheck valve mounted in the body for movement longitudinally thereoftoward and from said seat and between passage opening and closingpositions, mechanical motion transmitting means at each end of saidvalve adapted to receive force for effecting valve movements at thetravel limits of said plunger and means resisting valve movement fromboth positions-and comprising a permanent magnet mounted on the valvefor movement therewith and arranged with opposite poles spaced apart inthe longitudinal direction of movement, said magnet having a peripheralsurface of uniform radial dimension throughout its length between itsopposite poles and a body wall of magnetic material below said sea-t andsurrounding the magnet in uniform spaced radial clearance relation withthe magnet throughout the operating length thereof, said wall and saidvalve having lower terminal portions slidably fitted one to another tocenter and maintain said clearance relation and also having radialabutment surface for engagement at the limit of valve movement away fromsaid valve seat.

2. In a free plunger for wells, a hollow body having a passageway and avalve seat surrounding the passageway, a movable check valve forcontrolling the passage through the body, a valve carried permanentmagnet of uniform outside dimension and with its opposite poles spacedapart in the longitudinal direction of its movement, a valve retainingcage enclosing the valve and accommodating movement thereof to and fromsaid valve seat, interengaging seating surfaces on the valve and thecage engageable to limit the range of valve movement away from saidvalve seat, means on the valve to receive valve moving forces, said cagebeing carried by the body and provided with a surrounding wall ofmagnetic material and of a uniform inside dimension and interengagingcentering surfaces on the valve and body to provide substantially thesame clearance relation between the wall and the magnet in all relativepositions thereof.

3. In a free plunger as in claim 2, together with an outside facing ofnonmagnetic material lining the outside surface of the magnet.

4. A free plunger for travel in a well eduction tube, a hollow bodyhaving a peripheral sealing formation and a passageway through the body,a downwardly facing valve seat on the body in passageway surroundingrelation, a hollow valve cage having a wall of magnetic material andconstituting a downward extension of the body below said seat, a movablecheck valve slidably mounted within the valve cage for longitudinalvalve movement between an upper position in passageway closingengagement with the seat and a lower position in passageway openingrelation with the seat, an upwardly facing stop shoulder carried by thecage as an extension of the wall thereof and engageable by the checkvalve as a limit to valve movement toward said lower position, forcereceiving means at opposite ends of the valve for controlling valvemovement relative to the body and a permanent magnet forming a part ofand movable with the check valve and having opposite poleslongitudinally spaced apart and co-operating with said magnetic wall toresist valve movement away from both of said positions.

5. A free plunger for travel through a well eduction tube in theoperation of producing well liquid, a body having an outside diameterfor close fitment with an eduction tube and having an internal passagetherethrough, an upwardly seating check valve controlling said passage,top and bottom abutment surfaces on the valve for receipt of valveshifting forces, a hollow cage on the body having an annular wall ofmagnetic material enclosing the valve and being of uniform internaldiameter, a valve engageable seat projected inwardly on said wall andengageable by the check valve to limit shift thereof downwardly and apermanent magnet formed as a unit with the valve and arranged withlongitudinally spaced apart poles of similar outside dimension forsubstantially the same clearance relation adjacent said poles with theinterior surface of the cage Wall in all positions of the valve.

6. A well plunger for free travel in an eduction tube and comprising abody containing a fluid passage, a valve cage having a wall portion ofmagnetic material and constituting a fixed part of the body, a valveseat for the passage, a check valve movably housed within the cage,interengageable surfaces on the check valve and said cage engageablewith one another to limit valve movement away from said valve seat, saidcheck valve being mova ble for passage opening and closing relationswith the seat and including abutment surfaces on the valve to receivevalve movement force and a permanent magnet having its opposite polesspaced apart in the direction of valve movement for co-operation withthe magnetic wall portion of the cage in aliording a valve holdingeffect.

7. A well plunger for free travel in an eduction tube, comprising a bodycontaining a fluid passage and having a hollow portion constituting apart of the passage, said hollow portion providing a check valveenclosing chamber and having a chamber wall of magnetic material andalso having a lateral port through the wall intermediate itslongitudinal extent, a downwardly facing valve seat in the passage abovesaid lateral port, an upwardly facing stop shoulder in the chamber belowsaid port, a valve stem guide on said hollow portion extendeddownwardwardly below the stop shoulder, a valve stem having a lowerportion slidably fitted to said guide and adapted to transmit valvemoving force and having an upper portion projected into the chamber andterminated upwardly in a valve head for co-operation with said seat, amagnet mounted by the stem below said head with opposite poleslongitudinally spaced apart, a stop surface at the bottom of the magnetfor co-operation with said shoulder and a facing layer of nonmagneticmaterial overlying the peripheral surface of the magnet.

8. In a free plunger for travel within a well eduction tube, a hollowbody having eduction tube engageable sealing means peripherally thereonand providing a fluid passageway in the body with communicationexteriorly thereof above and below the sealing means, an upwardlyseating check valve for closing said passage way, a permanent magnetcarried by the valve and provided with opposite poles spaced apartlongitudinally of the direction of valve travel and a valve cage ofmagnetic material enclosing said valve and having top and bottom stopabutments engageable alternately by the valve and the upper of whichconstitutes an annular valve seat for said passageway, said stopabutments being longitudinaldy spaced apart a distance greater than thelongitudinal spacing between said poles and cooperating therewithwhereby the magnetic holding force on the valve is efiecltive at valveengagements repectively with the top and the bottom stop abutments andforce transmitting means on the check valve for the receipt ofmechanical force to shift the valve in opposition to the magneticholding force.

9. In a well plunger having a passageway therethrough, a valve cage ofmagnetic material forming part of said passageway and having a valveseat at one end of the cage and a valve stop longitudinally spaced fromsaid seat, a shiftable valve engageable with said seat at one limit toclose said passageway and with said stop at the other limit, valvecarried means positioned for receipt of mechanical valve shifting forceand a magnet carried by the valve and magnetized to present its oppositepoles spaced apart in the direction of valve movement for cooperationwith the seat and the stop respectively for a valve holding action.

10. In a magnetic check valve assembly, a pair of relatively shiftableelements, one of which is a body of magnetic material having apassageway and the other of which is a valve for the passageway, a pairof stop abutments of magnetic material on the body extending a mag neticflux path through the body and defining opposite limits of relativetravel and alternately engageable with said valve, a magnet constitutinga part of the valve and having its opposite poles spaced apart in thedirection of relative travel for magnetic attraction valve holdingco-operation with the magnetic abutments when either is engaged with thevalve and mechanical force responsive means on one of the elements foreffecting the relative shifting of said elements against opposition ofmagnetic attraction.

References Cited in the file of this patent UNITED STATES PATENTS

